Hot melt adhesives (HMA) are used in the hygiene industry as glue for nonwoven materials such as diapers. A significant share of the adhesive market in this segment is captured by HMAs based on styrene block copolymers (SBCs); the tackifiers used for HMAs based on SBCs are mostly hydrocarbon resins.
Hydrocarbon resins with low odour are an unmet need, while the odour of HMAs and the connection of odour to harmful chemicals has attracted negative attention around product safety. These concerns translate to pressure on marketers, formulators, and raw materials suppliers to work together to reduce odour, VOCs, and trace chemicals.
During processing of these resins, breakdown products may lead to the formation of odorous chemicals. Eastman has developed a technology that makes it possible to manufacture hydrocarbon resins with low odour and low amounts of trace chemicals. Chemical components such as aldehydes, alcohols, ketones, aliphatic hydrocarbons, and aromatic hydrocarbons are significantly reduced from the pure resin, and from the resin after aging for times applicable in the holt melt industry. Odour testing confirmed these results in a resin with a significantly improved odour profile. The samples developed with this technology also resulted in very low levels of trace chemicals and volatiles.